Lecture 2: Earth System

Question 1

What are the 4 spheres of the earth?

Answer 1

1. Geosphere (solid earth)
2. Hydrosphere (earths water)
3. Biosphere (life)
4. Atmosphere (earths envelope of gases)

Question 2

What is an isolated system?

Answer 2

This means that no energy can enter or escape

Question 3

What is a closed system? Give an example of a closed system.

Answer 3

Some energy can escape and enter
Earth is an example of a closed system, the sun is able to penetrate the atmosphere and earth is able to emit greenhouse gases

Question 4

What is an open system?

Answer 4

All energy is able to enter and escape

Question 5

How did earth originate?

How did it all begin?

Answer 5

It began with the Big Bang, a large explosion that sent radiation the universe flying outward, which expanded to atomic particles from e=mc^2. (conversion of energy to mass)

Question 6

How were the first stars produced

Answer 6

By the fusion of hydrogen atoms (producing helium and releasing energy in the process)

Question 7

How were planets formed

Answer 7

Stars began to explode, sending nebulae (clouds of gas and dust) around space, the matter then began to clump together (thanks to gravity), forming large clouds.
The sun was made from this cloud of matter, and the remaining matter spiralled around the sun, the solid particles fused together to make protoplanets.

Question 8

What are the inner rocky planets

Answer 8

Mercury
Venus
Earth
Mars

Thin atmospheres

Question 9

What are the outer gaseous planets

Answer 9

Jupiter
Saturn
Uranus
Neptune

Thick atmospheres

Question 10

How was earths interior heated?

Answer 10

1. Decaying of radioactive elements
2. Compaction of early earth
3. Meteorite impacts

Question 11

In earths molten interior, what happened with the metals?

Answer 11

The heavy metals sank to the core (iron rich core)
(Less dense mantle)
The lighter metals rose to the crust ( even less dense crust)

Question 12

What is earth’s core?

Answer 12

It’s a composition of iron-nickel alloy, it is very dense

Question 13

What is the difference between the core and the crust? (Mantle)

Answer 13

The difference between earths crust and core marks a change in the chemical composition

Question 14

What is earths crust?

Answer 14

Earths thin rocky outer shell

Question 15

How many atmospheres did earth have?

Answer 15

2: the first one was almost entirely helium and hydrogen (lost to space)
The second was produced by the outward forces of gases from its interior (CO2 and water vapour)

Question 16

How was the hydrosphere formed?

Answer 16

As earths interior began to cool, the water vapour that was sent outward by pressure could condense to make water…… then rivers lakes oceans, etc.

Question 17

How was the biosphere created?

Answer 17

Fossils (stromatolites) produced bacteria that was capable of photosynthesis

Question 18

In order, what was earths early internal structure? (exterior to interior)

Answer 18

Crust
Mantle
Core

Question 19

What is earths present day internal structure? Make reference to their state as well. (exterior to interior)

Answer 19

Lithosphere (solid brittle)
Asthenosphere (near-liquid brittle) 
Mesosphere (solid)
Outer core (liquid)
Inner core (solid)

Question 20

What are the three basic plate movements?

Answer 20

1. Divergent (away from one another)
2. Convergent (toward one another)
3. Transform (alongside one another)

Question 21

What is unique about earth?

Answer 21

it is the only planet that can host complex life and it is the only planet to have water of all 3 states at its surface (solid, liquid, gas)

Question 22

When was earth’s moon created?

Answer 22

around 50 billion years after the solar system took shape

Question 23

What is the lithosphere and how is it broken up?

Answer 23

It is the crust and the brittle part of the mantle. It is broken up by plates that float on the asthenosphere.

Question 24

What is Uniformitarianism, who formulated this concept?

Answer 24

“the present is key to the past” - james hutton
- this means that processes that produced earths geologic features can now be assumed to produce the same features in the past.